. >> my understanding is that the fbi's investigation into what took place on computers there did not -- was not necessarily focused on him. they came by the information by accident. >> law enforcement and multiple u.s. sources tell nbc news that e-mails between general petraeus and paula broadwell were indicative of an aextramarital affair. nbc was unable to reach paula for a comment. in his resignation letter, the retired four-star general revealed had he "show extremely poor judgment by engaging in an extramarital affair." sources tell nbc news that general petraeus is not under investigation. and that they don't expect their inquiry will result in criminal charges. petraeus was the man who turned around the wars in iraq and afghanistan. >> he's a figure here that people respected. >> but an affair that could have been embarrassing for any other public servant proved to be a career ender for the man trusted to keep the nation's secrets. brian mooar is, nbc news, washington. >> and still to come at 5:00, remembering those who died serving this country. we'll show you the ground brea